Remember that Arab-Kurdish Feud?

It’s hard to say whether things are heating up in Mosul between the Kurds and the Iraqi government or whether it’s the latest outbreak of a festering sore, but either way, it doesn’t look good:

The Shiite-led government of Prime Minister Nuri Kamal al-Maliki is squeezing out Kurdish units of the Iraqi Army from Mosul, sending the national police and army from Baghdad and trying to forge alliances with Sunni Arab hard-liners in the province, who have deep-seated feuds with the Kurdistan Regional Government led by Massoud Barzani.

The Kurds are resisting, underscoring yet again the depth of ethnic and sectarian divisions here and the difficulty of creating a united Iraq even when overall violence is down. Tension has risen to the point that last week American commanders held a series of emergency meetings with the Iraqi government and Kurdish officials, seeking to head off violence essentially between factions of the Iraqi government.

“It’s the perfect storm against the old festering background,” warned Brig. Gen. Raymond A. Thomas III, who oversees Nineveh and Kirkuk Provinces and the Kurdish region.

Worry is so high that the American military has already settled on a policy that may set a precedent, as the United States slowly withdraws to allow Iraqis to settle their own problems. If the Kurds and Iraqi government forces fight, the American military will “step aside,” General Thomas said, rather than “have United States servicemen get killed trying to play peacemaker.”

Many observers have assumed the flashpoint for an Arab-Kurdish war over Iraq’s northern regions would be sparked by unrest in Kirkurk. But perhaps Mosul is the real problem.

Actually, it seems the entire border zone of the Kurdish region is a problem, with intense personal animosity between Barzani and Maliki. There have been armed stand-offs between the Kurdish pesh merga and Iraqi Army units in Diyala, and Barzani has referred to the Iraqi prime minister as a new Saddam Hussein. It doesn’t help that Maliki is allying himself with Arabs from Mosul who have deep ties to the former regime, including the former general who led the invasion of Kuwait. He’s also been trying to purge the Army up there of its Kurdish leadership causing some officers to announce that their loyalty is to Kurdistan and not Iraq.

If tensions do erupt up north, things could get worse all over. First of all, it would renew questions of why the Americans are in Iraq if they’re not going to stop their two biggest allies from going at each other. Secondly, it could create a security vacuum that foreign fighters could exploit to start entering Iraq in larger numbers again. The exodus of Christians could worsen. And of course, the price of oil could start to creep up.